Electrical circuit control



Patented Sept. 14, 1948 ELECTRICAL CIRCUIT CONTROL Andrew S. Hegeman, In, Glen Ridge, and Harry N. Snook, Maywood, N. J., assignors to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application July 15, 1944, Serial No. 545,156

1 Claim. (Cl. 175-294) This invention relates to electrical circuit controls, and more particularly to circuit breakers.

An object of the invention is to provide an electrical circuit control which is rapidly-operable, accurate and readily reset.

With this and other objects in view, the invention comprises a control including a relay armature normally held against a contact to include an electrically operable unit in a circuit to a supply of electrical energy, the armature being movable free of the contact resulting from an overload current, to thus open the circuit to the unit.

Other objects and advantages will be apparent from the following detailed description when con- .sidered in conjunction with the wiring diagram illustrating the circuit control shown on the drawing.

Referring now to the drawing, reference numeral l designates a power supply for supplying electrical energy of a desired value and including terminals ii and I2. An electrical unit. indicated at i l, energlzable by electrical energy to be received from the supply in has electrical connectlons l and it. The electrical control, interposed between the supply ill and the unit it, is illustrated in its normal position, with an armature ll engaging its contact Hi. When in this, the normal position, a circuit is completed from terminal it through connection 2! armature ll, contact l8, connection 2!, reset switch 22, its break contact 23, connection 26, variable resistance 25, connection 26, to terminal l5, through the unit E l, terminal l6, back to the supply ill at terminal 52.

A polarized relay 28 has a primary winding tie, a secondary winding 30, and a tertiary winding 3|, which function jointly and severally to con trol the armature ll. When the circuit control is in the normal position shown and the e1ectrical energy is supplied to the unit i l, the primary winding 29 is connected in parallel with variable resistance 25 and in series with the unit it. The portion of the circuit for the primary winding 29 begins with connection 24 to connection 35, through the winding 29 and connection 26, to the unit I4 at terminal l5. At the same time the tertiary winding 35 is energized through a circuit extending from terminal ll, of the supply ill,

through connection 20, the winding 3!, resistancev 31 of a known value, connection 38, to supply it at terminal i 2. Although the windings 29, 30 and 3| appear to be in the same directions, the secondary winding 3t opposes the primary and tertiary windings 29 and i I. The circuit for the secondary winding, when the control is in the normal position shown, extends from the supply 10 at terminal ll through connection 20, armature ll, contact l8, connection 2|, through the secondary winding 30, resistance 40 of a known value, connection M, to the supply at terminal l2.

During normal conditions, with the unit l4 receiving the required electrical energy from the supply Hi determined by the setting of the resistance 25, the armature I! will .be held closed against the contact l8 through the magnetic force created in the polarized relay by the secondary winding 30. Thus the magnetic force created in the core of the relay 28 by the secondary winding 30 neutralizes the opposing magnetic force of the windings 28 and 31 to maintain this normal position.

Should an overload current pass to the unit M, an increase in the electrical energy will pass through the primary winding 29, creating an increased magnetic force in the primary winding, which, when added to that of the tertiary winding 3 I. will exceed the magnetic force of the secondary winding 30, resulting in the movement of the armature ll from its contact ill and into engagement with a contact 44. A a result of this action, the main circuit is opened to the unit it as well as to the primary and secondary windings 29 and ill, completing a circuit through an indicating lamp l5, this circuit being traced from the supply it at terminal ll, through connect-ion 2i], armature ll, contact 54, lamp cs, resistance 36, connection $7, to supply ill at terminal l2.

Through this movement of the armature l'l as previously stated, the primary and secondary windings are deenergized, the tertiary winding 3i remaining energized, however, to hold the armature closed against its contact M. The purpose of the condenser 33 and the resistance 35 in the circuit with the primary winding 29 is to provide contact protection acrws the contacts l8 and 44 and the reset key 22 by a resistance capacity network.

To reset the control, the key or switch 22 is moved from its contact 23 into engagement with a contact 50 to again complete a circuit through the secondary winding 30, this circuit being traced from the supply 50 at connection it through connection 20, contact 50, key 22, winding 30, resistance 40, connection 4l,-to the supply at terminal i2. The energization of the secondary winding 30 will neutralize the magnetic force of the tertiary winding 35 and thus force the armature ll into engagement with its contact 58. breaking its contact 44 to open the circuit to the lamp and pre are to again complete the main circuits to the unit I through the resistance 25 and also through the primary winding 29. After a suffl'cient time, determined by the deenergization of the lamp 45, has elapsed to allow for the resetting of the circuit. that is. for the movement of the armature from its contact 44 to its contact IS, the key 22 is released to thus complete the previously described main circuit, returning the control to normal.

Although specific improvements of the inven tion have been shown and described, it will be understood that they are but illustrative and that various modifications may be made therein without departing from the scope and spirit of this invention as defined by the appended claim.

What is claimed is:

An electrical circuit control, interposed between an electrical current supply and an electrically energizable unit comprising a polarized relay having a primary winding, a tertiary winding and an opposing secondary winding, the latter normally creating a magnetic force exceeding the combined normal magnetic force of the primary and tertiary windings, an armature for the relay actuable into open and closed positions to open and to close circuits from the supply and extending respectively through the unit, the primary winding and the secondary winding, the tertiary winding being included in a circuit extending directly from the supply, and a switch to initially complete a circuit from the supply through the secondary winding to cause movement of the armature into its closed position, the primary winding being aifected by an overload current to the unit to neutralize the magnetic efiect of secondary winding and with the magnetic force of the tertiary windings to cause movement of the armature into its open position and cause deenergization oi the primary and secondary windings and the unit, the magnetic force of the tertiary winding holding the armature in its open position.

ANDREW S. HEGEMAN, Jn.

HARRY N. SNOOK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 518,471 Smith Apr. 17, 1894 656,324 Holmes Aug. 21, 1900 1,204,485 Randall Nov. 14, 1916 1,298,464- Creveling Mar. 25, 1919 1,547,693 Schon et a1 July 28, 1925 1,594,275 Spain July 27, 1926 1,671,023 Fitzsimmons May 22, 1928 2,108,775 Macgeorge Feb. 15,1938 2,153,291 Bakker Apr. 4, 1939 2,170,964 Perry Aug. 22, 1939 2,359,175 Walley Sept. 26, 1944 

